The present invention relates generally to telecommunications systems and, in particular, to methods for processing global title translation requests within such telecommunications systems.
Telecommunications systems are well known in the art. A typical prior art telecommunications system 100, illustrated in FIG. 1, comprises telephones 102-103 coupled to switches 105-106. Communication paths used to convey user information, such as voice or data, are shown as solid lines between the telephones 102-103 and switches 105-106. Additionally, the system 100 also comprises a signaling network comprising Signal Transfer Points (STPs) 108-109, Service Control Points (SCPs; hereinafter alternatively referred to as xe2x80x9cservice processorsxe2x80x9d) 111-112, and a segmentation directory (SD) 114. Communication paths used to convey signaling information are shown as dotted lines between the STPs 108-109, SCPs 111-112 and SD 114. In the United States, these signaling links typically operate in accordance with the well-known Signaling System No. 7 (SS7) standard. For the purposes of clarity, less than all of the possible links between the system""s components are shown in FIG. 1. Because the telephones 102-103, switches 105-106, STPs 108-109 and SCPs 111-112 are well know in the art, their operation will not be discussed in further detail here. The segmentation directory 114 is described in further detail in U.S. Pat. No. 5,473,677 issued to D""Amato et al. and entitled TELECOMMUNICATIONS NETWORK ARCHITECTURE AND SYSTEM, the teachings of which patent are hereby incorporated by this reference. Generally, the segmentation directory allows for centralized processing of signaling messages and determination of services for a given call.
Within an SS7 network of the type described above, there are basically two different ways for routing a signal. First, the routing can be based on a combination of a point code (PC) and a subsystem number (SSN, hereinafter collectively referred to as a PC/SSN). When a PC/SSN is provided for a signal, each participating node (e.g., switches, STPs, SCPs, etc.) within the serving network must have data identifying the specified PC/SSN. Therefore, whenever a signal is received with a particular PC/SSN, each transferring node within the serving network knows exactly where to send the signal.
As an alternative, signals can also be routed using global title numbers. When the node originating a signal (e.g., a switch) does not know the PC/SSN associated with the destination node (e.g., a service processor), a global title number has to be used for routing purposes. Examples of global titles are toll-free 800/888 numbers and calling card numbers. Simply stated, each transfer node connecting the originating node with the destination node only knows to forward the received signal with a particular global title number toward a certain network or direction. At some point, a correct PC/SSN has to be provided so the signal can reach its final destination. This function is known as global title translation and is usually performed by an STP adjacent to the destination node. Thus, all of the STPs within a given network must include up-to-date information correlating global title numbers with specific PC/SSN information. While this method is currently acceptable, it becomes burdensome in light of the need to simplify the deployment of new services. That is, each time a new service is provisioned in the system or whenever new subscribers to existing services are added, the affected SCPs must be updated, the switch must be updated to request a new global title translation, and STPs must be updated to perform such a translation. Therefore, a need exists for a technique that provides current global title translation functionality and that simplifies service provisioning. In particular, it would be advantageous to use the centralized processing capabilities of segmentation directories to implement global title translation processing.
The present invention provides a technique for processing global title translation requests in a telecommunications system. Operating within a signaling network forming a portion of the telecommunications system, a segmentation directory completes global title translation by first performing a directory function based on information found in a services-related portion of a global title translation request. The segmentation directory of the present invention includes address information for substantially all customers subscribing to services in the system. The directory function results in call parameters that allow the segmentation directory to determine the point code/subsystem number of a service processor needed to complete the call. Modifying a transport-related portion of the global title translation request to correspond to the service processor previously identified, a modified version of the global title translation request is sent to the service processor. From the viewpoint of a switch that originated the global title translation request, it appears that normal global title routing has been used to address the service processor. However, because the segmentation directory can ascertain all of the necessary information to process the global title translation, the need for STP processing of the global title is eliminated. As a result, service provisioning is simplified because only a relatively small number of segmentation directories and/or service processors require updates, rather than a larger number of STPs and switches. The segmentation directory is also capable of handling exception and error conditions, thus simplifying overall system operation.